Nondiffusing phenolic color couplers



Patented Apr. 8, 1947 N ONDIFFUSING PHENOLIC COLOR COUPLERS Abraham Bavley, Binghamton, N. Y., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application May 20, 1944, Serial No. 536,602

4 Claims. 1

This invention relates to color photography and more particularly to a material in which color is produced in a photographic emulsion layer by the action of an oxidation product of a photographic developer on a dyestufi component incorporated in said layer.

The present invention is particularly concerned with a color forming development component adapted to be incorporated in a photographic emulsion layer, and which, when the emulsion layer is developed by means of a developer containing free amino groups, for instance, phenolic fdiamines, especially the monoor unsymmetrical- .ly disubstituted ones like p-dimethyl amino aniline, methoxy-p-dimethyl amino aniline, couple with the photographic developer to form a dyestuiT. The invention is thus an improvement on the process of color forming development which has first been disclosed in United States Patents No. 1,055,155 and No. 1,102,028 to Fischer.

As is known in such color forming development processes, certain phenols or hydroxy derivatives of benzene and naphthalene, especially those which in the para-position to the hydroxy group have either no substituent at all or a negative substituent such as, for instance, chlorine or sulfonic acid, when incorporated in a photographic emulsion, produce, on development of this layer with a color forming developer, blue dyestuffs.

It is an object of the invention to provide a new and improved blue dyestuff or color forming development component which produces a blue or green dye on color forming development. A further object is to provide such a novel color forming development component which may readily be rendered non-diffusible in a photographic emuls1on.

Other and further objects will be apparent as the present description progresses.

I have found that certain derivatives of salicylaldehyde, which are obtained by reacting salicylaldehyde with a primary amine, produce on development with a color forming developer, valuable dyes having a green color.

These new dyestuffs, which have the followin general formula:

in which R is an aryl, alkyl or aralkyl group of an amine or a polyalkylene polyamine group, and

X stands for a member of the group consisting of hydroxy and ester radicals and the group and in which the benzene ringmay be further substituted with a negative substituent as, for instance, a halogen or an acidic group such as chlorine, a sulfonic acid group or a carboxyl group, may readliy be produced by reacting salicylaldehyde with a hydroxy amine according to Equation I below:

Equation 1 The color forming development component A is non-diffusing if n is 8 or greater. In the event that n is less than 8, the component A may readily be rendered non-diffusing by known methods, for instance, by esterifying the same with a longchain fatty acid. Thus, if salicyladlehyde is reacted with monoethanol amine, a indicated in Equation I above, the color forming development component B below is obtained. Since 11. in compound B is 2, the component is relatively difiusible from one photographic emulsion layer to another. It may readily be rendered'non-diffusing, however, by esterifying the same with a suitable long-chain fatty acid containing 8 or more carbon atoms per molecule, such as stearic acid, as indicated in Equation II.

The color forming development component thus obtained, which is the stearyl ester of compound B, is relatively non-diffusible.

Similar color forming development components may be readily obtained by reacting salicylalde- 5 hyde with primary diamines in accordance with Equation III.

Equation III In this case aliphatic diamines may be employed, as indicated in Equation IV below, and if n is 8 or greater, I have found that the color forming Valuable non-difiusing color components can also be obtained by employing, as the diamine, various amino derivatives of compounds known to impart substantive properties to dyestuffs. Thus, if salicylaldehyde is reacted with benzidine or diamino stilbene, as indicated in Equatio V below, the color component E thus obtained is nondifiusing.

Equation V In certain respects, this feature of the present Equation VI The color forming development component F thus obtained is non-diffusing.

It should be understood that all the color forming development components mentioned above may have their solubility characteristics improved by sulfonation, so that a sulfonic acid substituent is incorporated in meta-position or para-position with respect to the hydroxy substituent. For the purpose of further illustration of the 7 present invention, the following specific examples are given. It should be understood, however, that these examples are illustrative only and it is not intended to limit the invention thereto.

Example 1 The color forming component C, in Equation II above, was prepared as outlined in Equations I and II by first condensing substantially equal molecular amounts of salicylaldehyde and monoethanolamine. This condensation was carried out by placing 15 grams of salicylaldehyde in a small beaker, cooled to -7 C. in .an acetone-dry ice bath. 7.5 grams of monoethanolamine was added in small portions with stirring. After the addition of each portion, the temperature, which rose rapidly, was allowed to go back to 0 C. :before any more of the amine was added. The resulting yellow liquid was distilled under vacuum, to yield 12 grams (61%,) of a viscous yellow oil. This product gave a green color on development with a color developer, p-diethylaminoaniline, but was not satisfactory for incorporation in a photographic emulsion as a color former, since its solubility was too great and it readily diffused from the photographic emulsion. Accordingly, the product was esterified with stearic acid and the thus obtained ester, color former C in Equation II above, was incorporated in a conventional silver halide photographic emulsion by dissolving a small :amount, .8 grams, in v3 cc. of

sodium hydroxide of 40% strength, 25 cc. of methanol and 7 0 cc. of water. The thus obtained solution was added to 500 cc. of gelatino silver halide emulsion of 5% strength. The thus obtained photographic emulsion could be cast on a suitable support to produce a photographic film, which after exposure and development with a color forming developer, p-diethylaminoaniline, gave a cyan picture.

Example 2' A color forming component whose formula corresponds to compound D in Equation IV above, in which n equals 18, obtained by condensing salicylaldehyde with stearyldiam'ine in a molar ratio of 2:1, this condensation being effected as outlined in Example 1 above by adding the amine to salicylaldehyde, with stirring, and while cooling to a temperature of approximately 0 C. or slightly lower. The product obtained was a yellow, sticky resinous mass, which was converted into a light-yellow crystalline solid by dissolving in acetone and precipitating by the addition of water. A 56% yield of crystalline product was obtained. This product was incorporated in a photographic silver halide emulsion in the manner outlined in Example 1 above. The thus obtained emulsion could be cast on a suitable support to produce a photographic film which, after exposure, gave, on development with a color forming developer, a green picture.

Example 3 The color forming component F, in Equation VI above, was obtained .by reacting salicylalde-j hyde with triethylenetetramine, using molar proportions of substantially 2:1, and cooling to approximately C., as outlined in Example 1. The product was a crystalline yellow solid, only slightly soluble in water, benzene and alcohol. Triturating with hot alcohol, cooling and filtering gave a product having a melting point of 120-122 C. A yield of substantially 100% was obtained. A slightly purer product, having a melting point of 122-123 C., was obtained by precipitating the product from an acetone solution by the addition of water. The product was incorporated in a conventional photographic silver halide emulsion, as outlined in Example 1, and was non-diffusing in such emulsion. The emulsion could be cast on a suitable support to produce a photographic film, which after exposure and development with a color forming developer gave a green color.

Example 4 Substantially equal molecular amounts of sali-' cylaldehyde, cooled to below 0 C., was reacted with h'ydroxyethyl-ethylenediamine by adding th amine, in small portions, with stirring, to the aldehyde. The temperature rose rapidly, after each addition, and the mixture was cooled back to 0 C. before the next portion was added. The product obtained was an orange-red oil, which was distilled to vacuum in order to remove the water, and after distillation, the product solidified to a waxy, yellow solid. This material gave a green color with color forming development but was too readily difiusible from photographic emulsions to be satisfactory therein. Accordingly, the product was esterified with lauric acid and the ester incorporated in a photographic emulsion, as outlined in Example 1 above. The lauryl ester was non-diffusing in the emulsion and the emulsion could be cast on a suitable support to produce a photographic film in accordance with conventional practice. On development with p-dimethylaminoaniline, a green picture was obtained.

Example 5 Th color forming development component E, in Equation V above, was obtained by condensing salicylaldehyde with diaminostilbene, using molar proportions of substantially 2:1 and the same conditions of reaction as specified in Example 1. The thus obtained color forming development component could be incorporated in' a photographic emulsion, as outlined in Example 1 above, and was non-difiusing therein. After casting the emulsion on a suitable support to produce a photographic film, a cyan picture was obtained on development with a color forming developer, pdiethylaminoaniline.

The foregoing examples are illustrative of preferred types of color forming development components, incorporating the features of the present invention. Many modifications thereof will suggest themselves to those skilled in the art, without departing from the spirit of this invention or the scope of the appended claims.

I claim:

1. A photographic silver halide emulsion layer having incorporated therein a color forming development component having the following formula:

in which R stands for a member of the group consisting of the residues of monohydroxy primary alkylamines containing at least 8 carbon atoms and esters thereof and the group in which n is an integer greater than seven.

2. A photographic silver halide emulsion layer having incorporated therein a color forming development component fast to diffusion having the following formula:

in which n is an integer greater than six.

3. A photographic silver halide emulsion layer having incorporated therein a color forming de velopment component fast to diffusion having the following formula:

in which n is an integer greater than seven.

4. A photographic silver halide emulsion layer having incorporated therein a color forming development component fast to diffusion having the following formula:

ABRAHAM BAVLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

